Lifting-jack.



and

eitiiaen ol the 'United States of America, and

particularly to that -a movable sleeve 12, to

FRANK L. GORMLEY, OF BOSTON, MASSACHUSETTS.

LIFTING-JACK.

Specification of Letters Patent.

.Patented July 27, 1909.

v.application filed February 16, 190i?. Serial No. 'iBOf.

h all whom 'it 'may ccmceracv be it .known that I, lfnmn L. Gourd-m', a

a resident of Boston, in the eoinity of Suffolk State ot Massachusetts, have invented certain new and useful lmprrwements in lliftingwlaeks, of which the following is ya specification.

This invention relates to lifting jadlfs and class of jacks which are known as ratchet screw jacks, and has for its object the provision of a means whereby the movable nieinber is prevented from being aecidentally lowered under. a heavy load.

The invention consists in interposhrg be-v tween the gear keyed to thelilfting screw and the inner face et the movable member two plates separated by means of a plurality of anti-friction members, the `lower plate being separated from the gear by means of a friction dislt and havingl peripheral teeth with which a plurality of spring-pressed pawls mounted in the movable member engage, to permit the free movement of the plate in one direction while it is prevented from rotating in the opposite direction.

The invention further consists in certain novel features of construction and arrangement of parts which will be readily 'underM stood by reference to the description of the drawings and to the claims hereinafter given.

0f the drawings: Figure 1 represents a horizontal section of a lifting` jack emlmdying 'the features of -this invention, the cutting plane 'being on linel--1 on Fig. 2. Fig. 2 represents a vertical section of the same, the. cutting plane being on line 2-2 on Fig. 1, and Fig. 3 represents an enlarged section of one of the operating pawls andthe devices cooperating therewith, the cutting plane be-` Siinilar characters 'designate like arts throughout the several figures of the i rawings.

ln the drawings, l() represents a suitable base supporting a stationary standard 11 over the outer periphery of which is fitted the upper end'oll which is threaded a cap 13. In the upper end ol' the standard 11 is mounted a nut 14 to which is threaded a lifting screw 15 hav-l ing splined to its upper reduced end a. gear 16 with which meshes a gear 17 formed upon or secured to a revoluble shaft 18, the outer end of which is provided with a suitable opi 1l)v ol" any well-known l the upperlace oi' the gear 1G is a friction dis; 23. The periphery of the plate .20 has 65 formed therein a plurality ol ratchet teeth 24 with 'which engage a plurality ol' piiwls 25 mounted in suitable depressions in the inner wall of the movable member 12 and each inoifnbleabout a pivot pin 26. pawl is provided on its outer side with ax. beveled lace with which engages the beveled end o1' a pin 28 which is prevented from turning by nien-ns ol' a threaded member 29 mounted in the movable member 12 and75 of said pin 28.',

blurring against a ilnt side This beveled pin movable longitud#l nelly in. the hole in which it is mounted and is pressed downwardly into Contact with the. beveled face of the a spring 30. Each spring :iets upon its pin 2S to force one of the pawls 25 into engage-vl nient with the ratchet teeth 24 l'ornied upon the periphery ol the plate 20.

The weight upon the ea'fp 13 is sulieient 8- 5 to cause considerable i'riction between the` plate 20, disk 23, andgear 16, so that when l the gear `1G is rotated in the direction olA the arrow on 1 the plate 2O will be carried thereby and the various pawls over the ratchet teeth 24,. v

Should any extreme weight supported by the jack tend to cause the screw 15 to inove, downwardly inA .its nut Plon-'ing to the coarse 'pitch tl1e1eoil,-tl1e 'gear 16 would be caused95 i to rotate int-he opposite direction to that indicatedlby the yarrowon Fig; 1 and the teeth 24 of the plate 20 carried thereby would immediately come into engagement withl the pawls 25 and be rotation in that direction' around the redueedshank 31 ol thel screw 15. When thev rotation of the plate 20 is thus prei-*ented in order for .the screwy lgt'o-'move downwardly in the nut 14, it is'neeessary that the gear 16' 4:1.05 ,should eontinueto rotate 1n a direction ijs-. verse to that indicatedI by the arrow on Fig. r i

1, and this 'tendency to rotate in this direction would'be prevented by the extra l'rlction existing between the plate 20, -friction 110 disk 23, and gear 16, although it is obvious that when power is applied to the operatnlg esp 13 are 60 Each 7o pawl 25 by means of 8e 25 vwill ride 90,l

prevented l'romifurther 1 vmechanism. to lower the movable memberA -by turning the gear 16 in said reverse direction that this friction vwill be overcome and permit the necessary lowering ofthe weight. It is obvious that by vsuch a construction as is herein set iorth and described, any aon c idental lowering,` oll the movable member of the jack is wholly obviated, i-t being seit evident that such accidental lowering is dangerous and objectionable.

lt is believed that 'from the foregoing" the operation and many advantages of the invention will be thoroughly understood.

Having 'thus described my invention, .l i5 claim: A

l. In a lifting); jack, the combination of a stationary member; a movable member thereon; a revoluble member for raising and lowering said movable member; means for rotatingsaid revoluble member; an annular `plate interposed between said movable inem-f ber and said revoluble member and in frict-ional. contact with said revoluble member; yand means between said movable member 2'5iand plate to insure the simultaneous rotation of said plate and revolubie member in one directionwhile permitting movement of said revoluble member in the opposite direc-Y tion. 2. in a lifting jackLthe combination of a stationary member; a movable member thereon; a 'screw for said movable member; fmeans for rotating said screw; an annular i late interposed between said movable member and screw and having peripheral teeth; and means secured to said movable meinber and co-aeting with said teeth to insure i the simultaneous rotation of said plate and screw in one direction while permitting in.- /40 dependent movement of said screw nr the o per and screw and having peripheral teeth; a

friction disk interposed between said plate and screw; and means secured to said movable member and coacting with said teeth to insure the simultaneous rotation of said plate and screw in one direction while peiL mittingl independent movement of ,said screw in the opposite direction. l

4. in a lifting; jack, the combinatirnrot a stationary member; movable member thereon; a screw for said movable member; .means for rotating said screw; an amniiar pia-teinterposed between said movable mem-V bei' and screw and having peripheral teeth; a y friction dish interposed between said plate and screw; and a pawl secured to said movseater able member and co-acting with said teeth to insure t-he simultaneous rotation of said plate and screw in one direction While permitting independent movement of said screw in the opposite direction.

5. ln a lifting iack, the combination of a stationary mem er; a movable' member thereon; a screw for saidl movable member; means for rotating said screw; an annular plate interposed between said movable memver and screw and lnrvingY peripheral teeth; a friction disk interposed between said plate and screw; and a spring-o )erated pawl secured to said movable member and (zo-acting with said teeth to insure the simultaneous rotation ol' said plate'and screw in one direction*` while permitting;a independent movement of' said screw in the opposite direction.

(3. In a lifting jack, the `eombinfnbion of a stationary member; a movable member thereon; a screw for said movable member; means 'r'or rotating said screw; an annular' )late ii'iterposcd between said movable memer and screw and having peripheral teeth; a friction dish interposed between s'aid plate and screw; a spring-operated pawl, having an inclined lace secured tosaid movable member and conf-,ting with said teeth to insure the simultaneous rotation of said plate and screw in one direction while permitting independent'movement of said screw in the opposite direction; and 'a spring-operated .beveled member eoaeting with said inclined face to normally retain said pawi in engagement with said teeth.

7. ln a lifting jack, the combination of a stationary member; a movable member thereon; a screw and nut tor raising and low ering said movable member, one of which is revoluble; a plate disconnected from but frictionaily contacting with. said revoluble member and provided withperipheral teeth; and means secured to said movable member co-acting with said teeth to permit the rotatfionof said plate in one direction only.

8. In a lifting` jack, the combination of a stationary member; a movable member thereon; a screw and nut for raising` and lowering' said movable member, one of which is revolubie; a plate disconnected frcm; but frictionaily contacting with said revolnble member and provided with peripheral teeth; and a pawl secured Lo said movable member co-actin {`I- with said teeth to permit the rota* tion of said plate in one directiononly.

Signed by me at 4 Post Oiee Sq., Boston,

Mass., this -Sth day oli' February7 i909.

FRANK L. GORMLEY. Witnesses WALTER E. hermann, NATHAN i l. LOMB/inn. 

